JP2009040739A - External preparation for skin for protecting ultraviolet ray - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for improving the stability of ascorbic acid or its derivative and the stability of zinc oxide in an emulsifier type external preparation for skin, containing the ascorbic acid or its derivative and the zinc oxide. <P>SOLUTION: This water-in-oil emulsifier type external preparation for the skins is characterized by containing (1) a clay mineral modified with an organic material, (2) zinc oxide, and (3) ascorbic acid or its derivative. The clay mineral modified with an organic material is preferably hectrite modified with distearodimonium, and the ascorbic acid or its derivative is preferably preliminarily dispersed and contained in an aqueous phase. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an external preparation for skin, and more particularly to an external preparation for skin suitable for UV protection.

  In recent years, in view of the existence of ozone holes caused by fluorocarbon and carbon dioxide, awareness of protection against ultraviolet rays has increased. In particular, the intention to care for the ultraviolet ray A, which has not been so much conscious until now, is increasing in the same manner as the ultraviolet ray B. Care for ultraviolet rays B can be sufficiently achieved by combining a masking agent such as titanium dioxide with a cinnamic acid ester type ultraviolet absorber or an aminobenzoic acid type ultraviolet absorber. The current situation is dependent on zinc oxide. Such zinc oxide is an amphoteric metal oxide, and there have been cases where hydrolysis is partially caused by coexisting components and disturbs the stability of the system. In particular, in the presence of production components such as ascorbic acid and its derivatives, this tendency is high, and coloring of ascorbic acids also occurred. From such a point of view, attempts have been made to improve the stability of water-in-oil emulsifiers by incorporating ascorbic acid or a derivative thereof (for example, see Patent Document 1 and Patent Document 2). However, it has not yet been put to practical use.

  On the other hand, a method for preparing a water-in-oil emulsifier type skin external preparation using the emulsifiability of an organically modified clay mineral is already known (for example, see Patent Document 3). In addition, it is already known that zinc oxide is contained in a water-in-oil emulsifier form using an organically modified clay mineral to obtain an ultraviolet protective cosmetic (see, for example, Patent Document 4 and Patent Document 5). However, there is no known technology for incorporating ascorbic acid or its derivative into a water-in-oil emulsifier form of an organically modified clay mineral, and 1) an organically modified clay mineral, 2) zinc oxide, and 3) ascorbic acid or There is also no known skin external preparation in the form of a water-in-oil emulsifier containing the derivative. In addition, it has not been known at all that adopting such a configuration improves both the stability of ascorbic acids and the stability of zinc oxide in such a preparation system.

JP 02-83309 A WO99 / 33439 JP 11-246354 A Japanese Patent Laid-Open No. 2005-232069 Japanese Patent Laid-Open No. 10-212224

  The present invention has been made under such circumstances. In an emulsifier-type skin external preparation containing ascorbic acid or a derivative thereof and zinc oxide, the stability of ascorbic acids and the stability of zinc oxide are achieved. It is an issue to provide a technology that improves both of the performance.

In view of such a situation, the present inventors, in an emulsifier-type skin external preparation containing ascorbic acid or a derivative thereof, and zinc oxide, showed the stability of ascorbic acids and the stability of zinc oxide. As a result of earnest research efforts in search of technology that can improve the quality of both, we have found that such stability can be obtained by using water-in-oil dosage forms using organically modified clay minerals. The present invention has been completed. That is, the present invention is as follows.
<1> A skin external preparation in the form of a water-in-oil emulsifier containing 1) an organically modified clay mineral, 2) zinc oxide, and 3) ascorbic acid or a derivative thereof.
<2> The skin external preparation according to <1>, wherein the organically modified clay mineral is hectorite modified with a disteadiromonium salt.
<3> The external preparation for skin according to <1> or <2>, wherein the zinc oxide is previously dispersed in an oil phase.
<4> The external preparation for skin according to any one of <1> to <3>, wherein the ascorbic acid or the derivative thereof is dispersed and contained in advance in an aqueous phase.
<5> The aqueous phase in which the ascorbic acid or a derivative thereof is dispersed has a pH adjusted to 6 to 7 with a buffer salt, <1> to <4>, The skin external preparation as described.
<6> The external skin preparation according to <5>, wherein the buffer salt is citric acid or a salt thereof.
<7> The external preparation for skin according to any one of <1> to <6>, wherein the oil phase contains a fatty acid that is liquid at 1 atmosphere and 25 ° C.
<8> The fatty acid according to <7>, wherein the fatty acid which is liquid at 1 atm and 25 ° C. is a fatty acid having a branched chain having 12 to 24 carbon atoms.

  The present invention provides a technique for improving both the stability of ascorbic acids and the stability of zinc oxide in an emulsifier-type skin external preparation containing ascorbic acid or a derivative thereof and zinc oxide. be able to.

(1) Organically modified clay mineral which is an essential component of the external preparation for skin of the present invention The external preparation for skin of the present invention is characterized by containing an organically modified clay mineral as an essential component. Here, organic modification means that a part or all of the properties of an organic compound is made into a clay mineral by causing a part of the organic compound to form a strong or loose bond via a covalent bond or an ionic bond. This means that it is imparted to minerals. Examples of such modifications include a method of binding a quaternary amine group and an anion portion of a clay mineral, and a method of binding a carboxyl group and a cation portion of a clay mineral. A method of combining the group and the anion portion of the clay mineral is particularly preferable. Although it does not necessarily limit as a compound which has a quaternary amino group which modifies a clay mineral, The compound called quaternium is illustrated. Quotanium is a low molecular weight substituted quaternary ammonium salt, and is preferably a cosmetic raw material registered in International Standard Cosmetic Ingredients (INCI). Furthermore, the compound having a quaternary amino group that modifies the clay mineral is preferably a quaternium compound contained in a conventional external skin preparation among quaternium compounds. Preferred examples of the quaternium compound used in conventional external preparations for skin include stearyl trimethyl ammonium chloride and dimethyl distearyl ammonium chloride. Stearyl trimethyl ammonium chloride, dimethyl distearyl ammonium chloride, and the like are preferable because they can form a stable water-in-oil emulsion structure together with clay minerals. On the other hand, as a clay mineral (unmodified clay mineral) modified with a compound having a quaternary amino group, any clay mineral contained in a conventional external preparation for skin can be used without particular limitation. Preferred clay minerals contained in conventional skin external preparations include smectite-type hectorite, bentonite and montmorillonite; kaolinite; illite; marine clay mineral (sea mud); desert rose clay mineral; Among these, bentonite, hectorite, montmorillonite or kaolinite which can stabilize the water-in-oil emulsion structure is preferably exemplified. An example of a method for producing a clay mineral modified with a compound having a quaternary amino group contained in the external preparation for skin of the present invention will be described below. The unmodified clay mineral is dispersed in a dispersion medium. The dispersant is preferably an aqueous solvent, and may be water. A compound having a quaternary amino group is further added to the dispersion containing the dispersed unmodified clay mineral and stirred well. The compound having a quaternary amino group may be added after being dissolved in water. The amount of the compound having a quaternary amino group to be added is preferably 0.1 to 20% by mass, and more preferably 0.5 to 15% by mass with respect to the amount of the dispersed unmodified clay mineral. This is because by taking such a configuration, a preferable feeling of use is exhibited in the emulsion system. After stirring, the dispersoid is filtered, dehydrated and dried to obtain the modified clay mineral in the present invention. Or the modified clay mineral in this invention can also be obtained by removing a dispersing agent by concentrating under reduced pressure without filtering a dispersoid, and making it dry. The obtained modified clay mineral is preferably pulverized to a desired size (preferably having a particle size of 1 to 1000 μm) and contained in the skin external preparation of the present invention. The modified clay mineral in the present invention can be prepared and used as described above, but a commercially available one can also be used. Some modified clay minerals on the market are used as external preparations for skin such as cosmetics. Preferable examples of commercially available modified clay minerals include dimethyl distearyl ammonium modified hectorite sold under the name “Benton 38V” by Elementis. In the skin external preparation of this invention, this component is contained preferably 0.5-10 mass%, More preferably, 1-5 mass% is contained. Such components are excellent in the action of forming a high internal phase water-in-oil emulsion. Individually, the water-in-oil emulsifier form referred to in the present invention is a general term for an emulsifier form whose outermost phase is an oil phase, and is a generic term for a water-in-oil emulsifier form, an oil-in-water oil-in-water emulsifier form, and the like.

(2) Zinc oxide which is an essential component of the external preparation for skin of the present invention The external preparation for skin of the present invention is characterized by containing zinc oxide as an essential component. Zinc oxide is a concealing agent that absorbs not only ultraviolet rays B but also ultraviolet rays A. In the external preparation for skin of the present invention, it is blended for the purpose of protecting the skin from ultraviolet rays A and ultraviolet rays B. For the said objective, it is preferable to contain 5-30 mass% of zinc oxide, More preferably, it is 10-25 mass%. Here, since zinc oxide is an oxide of an amphoteric metal, it reacts with both an acidic component and a basic component in the presence of water to form a salt or a partial salt. Therefore, if it exists in the aqueous phase, it reacts with ascorbic acid or its derivatives described later, and in some cases, base exchange is performed to form a salt. The formation of such a salt often impairs the stability of ascorbic acid or its derivatives. To avoid this, zinc oxide is previously dispersed in the oil phase, and an aqueous phase is added thereto. And emulsifying. At this time, if a fatty acid is present in the oil phase at 1 atm. 25 ° C., it partially binds to the surface of zinc oxide, and its lipophilicity is enhanced, thereby increasing dispersibility in the oil phase. At the same time, after emulsification, the orientation of zinc oxide in the aqueous phase is inhibited, so that stability is improved, which is preferable. As the fatty acid that is liquid at 1 atm and 25 ° C., an unsaturated fatty acid having 12 to 24 carbon atoms or a branched fatty acid is preferable, and a branched fatty acid is particularly preferable in view of light stability. Specifically, examples of the unsaturated fatty acid include oleic acid, linoleic acid, linolenic acid, and lithinolic acid, and examples of the branched fatty acid include isostearic acid and isopalmitic acid. The content is preferably 0.1 to 5% by mass, more preferably 0.2 to 0.5% by mass.

(3) Ascorbic acid or a derivative thereof as an essential component of the external preparation for skin of the present invention The external preparation for skin of the present invention is characterized by containing ascorbic acid or a derivative thereof as an essential component. Examples of the derivatives of ascorbic acid include salts of ascorbic acid, esters of ascorbic acid and phosphoric acid and salts thereof, glycosides of ascorbic acid such as ascorbic acid-2-glucoside, and salts thereof, and the like. Can be included. Examples of the salt include alkali metal salts such as sodium salt and potassium salt, alkaline earth metal salts such as calcium salt and magnesium salt, organic amines such as ammonium salt, triethylamine salt, triethanolamine salt and monoethanolamine salt. Preferred examples include basic amino acid salts such as salts, lysine salts, and alginates. These ascorbic acids or derivatives thereof are preferably water-soluble, and are preferably dissolved in the aqueous phase in advance. Such ascorbic acid or a derivative thereof inhibits the inflammation caused by irradiation with ultraviolet rays or the like by releasing the active oxygen from the inflammatory factor and further increasing the degree of inflammation by eliminating the active oxygen. . At the same time, it suppresses the increase in melanin production following inflammation and suppresses pigmentation. Furthermore, radicals generated from zinc oxide which absorbs ultraviolet rays and whose electronic state is excited are immediately erased, and its damage is suppressed. In this way, the damage to the living body caused by ultraviolet rays is reduced by suppressing secondary damage of ultraviolet rays. In order to achieve such an effect, the ascorbic acid or derivative thereof is preferably contained in a total amount of 0.1 to 10% by mass, preferably 1 to 5% by mass, based on the total amount of the external preparation for skin. It is more preferable.

(4) External preparation for skin of the present invention The external preparation for skin of the present invention contains the essential components and is in the form of a water-in-oil emulsifier. The external preparation for skin of the present invention can contain, in addition to such components, optional components that are usually used in external preparations for skin. Such optional ingredients include, for example, macadamia nut oil, avocado oil, corn oil, olive oil, rapeseed oil, sesame oil, castor oil, safflower oil, cottonseed oil, jojoba oil, coconut oil, palm oil, liquid lanolin, hydrogenated coconut oil Oil, wax, oil such as beeswax, canola wax, carnauba wax, ibotarou, lanolin, reduced lanolin, hard lanolin, jojoba wax, liquid paraffin, squalane, pristane, ozokerite, paraffin, ceresin, petrolatum , Hydrocarbons such as microcrystalline wax; higher fatty acids such as oleic acid, isostearic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, undecylenic acid; cetyl alcohol, stearyl alcohol, isostearyl Higher alcohols such as alcohol, behenyl alcohol, octyldodecanol, myristyl alcohol, cetostearyl alcohol; cetyl isooctanoate, isopropyl myristate, hexyldecyl isostearate, diisopropyl adipate, di-2-ethylhexyl sebacate, cetyl lactate, malic acid Diisostearyl, di-2-ethylhexanoic acid ethylene glycol, dicaprate neopentyl glycol, di-2-heptylundecanoic acid glycerin, tri-2-ethylhexanoic acid glycerin, tri-2-ethylhexanoic acid trimethylolpropane, tri Synthetic ester oils such as trimethylolpropane isostearate and pentane erythritol tetra-2-ethylhexanoate; dimethylpolysiloxane, methylphenylpoly Linear polysiloxanes such as oxane and diphenylpolysiloxane; cyclic polysiloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexanesiloxane; amino-modified polysiloxane, polyether-modified polysiloxane, alkyl-modified polysiloxane, Oil agents such as silicone oils such as modified polysiloxanes such as fluorine-modified polysiloxanes; Anionic surfactants such as fatty acid soap (sodium laurate, sodium palmitate, etc.), potassium lauryl sulfate, triethanolamine ether of alkyl sulfates; Cationic surfactants such as stearyltrimethylammonium, benzalkonium chloride, laurylamine oxide; imidazoline-based amphoteric surfactants (2-cocoyl-2-imida Zolinium hydroxide-1-carboxyethyloxy disodium salt, etc.), betaine surfactants (alkyl betaine, amide betaine, sulfobetaine, etc.), and amphoteric surfactants such as acylmethyltaurine; sorbitan fatty acid esters (sorbitan) Monostearate, sorbitan sesquioleate, etc.), glycerin fatty acids (glyceryl monostearate, etc.), propylene glycol fatty acid esters (propylene glycol monostearate, etc.), hardened castor oil derivatives, glycerin alkyl ethers, POE sorbitan fatty acid esters (POE sorbitan monooleate, polyoxyethylene sorbitan monostearate, etc.), POE sorbite fatty acid esters (POE-sorbitol monolaurate, etc.), POE glycerin fatty acid ester Tells (POE-glycerol monoisostearate, etc.), POE fatty acid esters (polyethylene glycol monooleate, POE distearate, etc.), POE alkyl ethers (POE2-octyldodecyl ether, etc.), POE alkyl phenyl ethers (POE nonylphenyl) Ethers, etc.), Pluronic types, POE / POP alkyl ethers (POE / POP2-decyltetradecyl ether, etc.), Tetronics, POE castor oil / hardened castor oil derivatives (POE castor oil, POE hardened castor oil, etc.), Nonionic surfactants such as sucrose fatty acid ester and alkyl glucoside; polyethylene glycol, glycerin, 1,3-butylene glycol, erythritol, sorbitol, xylitol, maltitol, propylene Polyhydric alcohols such as recall, dipropylene glycol, diglycerin, isoprene glycol, 1,2-pentanediol, 2,4-hexanediol, 1,2-hexanediol, 1,2-octanediol; sodium pyrrolidonecarboxylate Moisturizing ingredients such as lactic acid and sodium lactate; powders such as mica, talc, kaolin, synthetic mica, calcium carbonate, magnesium carbonate, anhydrous silicic acid (silica), aluminum oxide, barium sulfate, etc. whose surface may be treated Body, the surface may be treated, inorganic pigments such as bengara, yellow iron oxide, black iron oxide, cobalt oxide, ultramarine, bitumen, titanium oxide, zinc oxide; surface may be treated, mica Pearl agents such as titanium, fish phosphorus foil, bismuth oxychloride; red 202 which may be raked, red Color 228, Red 226, Yellow 4, Blue 404, Yellow 5, Red 505, Red 230, Red 223, Orange 201, Red 213, Yellow 204, Yellow 203, Blue 1 No., Green 201, Purple 201, Red 204, etc .; Organic powders such as polyethylene powder, polymethyl methacrylate, nylon powder, organopolysiloxane elastomer; Paraaminobenzoic acid UV absorbers; Anthranils Acid UV absorbers; salicylic acid UV absorbers; cinnamic acid UV absorbers; benzophenone UV absorbers; sugar UV absorbers; 2- (2′-hydroxy-5′-t-octylphenyl) benzo UV absorbers such as triazole and 4-methoxy-4′-t-butyldibenzoylmethane; lower alcohols such as ethanol and isopropanol Cole; Vitamin A or derivatives thereof, vitamin B6 hydrochloride, vitamin B6 tripalmitate, vitamin B6 dioctanoate, vitamin B2 or derivative thereof, vitamin B12 such as vitamin B12, vitamin B15 or derivative thereof; α-tocopherol, β- Preferred examples include vitamins such as tocopherol, γ-tocopherol, vitamin E acetate and the like, vitamins D, vitamin H, pantothenic acid, panthetin, pyrroloquinoline quinone, and the like; and antibacterial agents such as phenoxyethanol.

  Among these, as a particularly preferred component, polyether-modified silicone can be exemplified to assist the emulsifiability of the organically modified clay mineral. Preferred examples of the polyether-modified silicone include polyethylene glycol-modified methyl siloxane, polypropylene glycol-modified methyl siloxane, and polyethylene glycol / polypropylene glycol-modified methyl siloxane. Particularly preferred is polyethylene glycol (10) -modified methylsiloxane, which includes, for example, “silicone KF6017” manufactured by Shin-Etsu Chemical Co., Ltd. as a commercial product. The preferable content of such a polyether-modified silicone is 1 to 20% by mass, and more preferably 5 to 15% by mass, based on the total amount of the external preparation for skin.

  The skin external preparation of this invention can be manufactured by processing the said essential component and an arbitrary component in accordance with a conventional method. As an external preparation for skin of the present invention, for example, cosmetics including quasi-drugs, pharmaceutical compositions for external use for skin, sundries for external use, etc. can be applied to those externally administered to the skin. Particularly preferred examples include cosmetics. Moreover, if the dosage form takes a water-in-oil emulsified form, it can take a state of emulsion, cream, solid or semi-solid. Hereinafter, the present invention will be described in more detail with reference to examples.

  According to the formulation shown below, an ultraviolet protective cosmetic that is an external preparation for skin of the present invention was prepared. That is, the component (a) was made into a uniform dispersion with a covol mill, and then the temperature was adjusted to 80 ° C. together with the component (b). After adding the ingredients of C to this and further uniformly dispersing under stirring, the mixture was preheated to 80 ° C., and uniformly solubilized ni was gradually added to emulsify, stirred, cooled and cosmetics. 1 was obtained. Similarly, Comparative Example 1 in which zinc oxide was replaced with titanium dioxide, Comparative Example 2 in which ascorbic acid glucoside was replaced with arbutin, and Comparative Example 3 in which zinc oxide was replaced with titanium dioxide and ascorbic acid glucoside was replaced with arbutin were also prepared. .

<Test Example 1>
Using cosmetic 1, comparative example 1, comparative example 2 and comparative example 3, the ultraviolet protective effect was compared. In other words, 5 parts of 2cm x 3cm are created on the back, each sample is applied to 4 parts, light is shielded without applying anything to the remaining 1 part, SE lamp and BLB lamp are installed. The same number of light sources mixed with ultraviolet part A and ultraviolet part B were used to irradiate twice the amount of erythema. This work was performed for 14 days every day. 24 hours after the end of the last treatment, the color difference (ΔE) between the non-administration light-shielded site and the sample-administered site was measured using a Konica Minolta CR400 “color difference meter”. (Example 1) The results are shown in Table 2. This shows that the skin external preparation of this invention has the outstanding ultraviolet-ray protective effect.

<Test Example 2>
Using cosmetic 1, comparative example 1, comparative example 2 and comparative example 3, a storage test at 50 ° C. for 2 weeks was conducted. The sample was returned to 20 degreeC after completion | finish of storage, the state was observed, and the color difference with a 5 degreeC preservation | save goods was calculated | required. The results are shown in Table 3. This shows that the external preparation for skin of the present invention is excellent in stability.

  In the same manner as in Example 1, cosmetic 2 was produced according to the following formulation. This was evaluated in Test Example 1 and had a ΔE of 0.23. Further, in the evaluation of Test Example 2, the color difference was 0.41, and it was found that the addition of the branched fatty acid was preferable to the addition of the unsaturated fatty acid.

  In the same manner as in Example 1, cosmetic 3 was produced according to the following formulation. This was evaluated in Test Example 1 and had a ΔE of 0.35. In the evaluation of Test Example 2, the color difference was 0.56, and it was found that the addition of liquid fatty acid was preferable.

  In the same manner as in Example 1, cosmetic 2 was produced according to the following formulation. This was evaluated in Test Example 1 and had a ΔE of 0.32. In the evaluation of Test Example 2, the color difference was 0.61, and it was found that addition of citrate buffer salt to the aqueous phase was preferable.

  The present invention can be applied to skin external preparations such as cosmetics for UV protection.

Claims (8)

A skin external preparation in the form of a water-in-oil emulsifier containing 1) an organically modified clay mineral, 2) zinc oxide, and 3) ascorbic acid or a derivative thereof. The external preparation for skin according to claim 1, wherein the organically modified clay mineral is hectorite modified with a disteadiromonium salt. The external preparation for skin according to claim 1 or 2, wherein the zinc oxide is dispersed and contained in advance in an oil phase. The external preparation for skin according to any one of claims 1 to 3, wherein the ascorbic acid or a derivative thereof is dispersed and contained in advance in an aqueous phase. The skin external preparation according to any one of claims 1 to 4, wherein the pH of the aqueous phase in which the ascorbic acid or its derivative is dispersed is adjusted to 6 to 7 with a buffer salt. . The skin external preparation according to claim 5, wherein the buffer salt is citric acid or a salt thereof. The skin external preparation according to any one of claims 1 to 6, wherein the oil phase contains a fatty acid which is liquid at 1 atm and 25 ° C. The fatty acid according to claim 7, wherein the fatty acid that is liquid at 1 atm and 25 ° C. is a fatty acid having a branched chain having 12 to 24 carbon atoms.